SQL Server Tips by Robin Schumacher

Design Success

Many DBAs believe that code inefficiency is the number one cause of system problems. As previously mentioned, many rules of thumb turn out to be untrue, and this is one of them.

The number one cause of performance-related problems, as well as system outages, is simply bad design. Tragically, this is not only the number one cause of speed and availability headaches, but it is also the most difficult to model in terms of declaring a database design good or bad overall.

For example, how can the DBA easily tell if denormalizing a set of tables into one object will accelerate performance? In the world of RAID and fast I/O devices, how can it be known whether separating tables and indexes onto different physical drives will enhance speed, or if another index is needed on a large dimension-styled table?

Unfortunately, design success cannot be measured as easily or evaluated as quickly as the other components in the performance model.

The above book excerpt is from:

High-Performance SQL Server DBA
Tuning & Optimization Secrets

ISBN: 0-9761573-6-5
Robin Schumacher

 http://www.rampant-books.com/book_2005_2_sql_server_dba.htm